The invention described here may be made, used and licensed by the United States Government for governmental purposes without paying me any royalty.
1. Field of the Invention
In one aspect this invention relates to vehicle structures. In a further aspect this invention relates to military vehicles having blast protection devices.
2. Prior Art
When a ground vehicle passes over a land mine, the blast creates a large dynamic load on the vehicle structure which in turn frequently causes the vehicle latches to fail and the doors to fly open. Once the doors are open, the occupants can be easily stuck by blast forces, blast debris and possibly be ejected from the vehicle causing injury. Since land mines are relatively cheap, they have become ubiquitous in many parts of the world. Therefore, land mine encounters are becoming increasingly common as military troops take on peace keeping and other quasi-military missions in many parts of the world where they operate wheeled vehicles in unfamiliar and dangerous terrain. This has resulted in many injuries even where the vehicle has a blast shield disposed underneath the cab that will prevent the blast from collapsing the cab protecting the vehicle cab and preventing debris and shrapnel from entering the cab.
Present, solutions to the problem of sudden door opening due to blasts, consist of positive latching mechanisms such as sliding bolt type closures. Such closures have major disadvantages in that they require positive action to latch with the result that human error can result in the latch not being used. This is particularly true when the vehicle is being used under hostile conditions where speed is essential and the vehicle occupants are under stress. Further once latched, the doors require a positive operation to unlatch. This could create a safety condition should it be necessary to exit the vehicle rapidly; particularly if the latch has been jammed or there is some sort of misalignment as a result of a blast.
What is needed is a safety mechanism that deploys automatically to prevent unwanted door opening when needed to keep the doors closed and which does not interfere with the door""s normal operation under normal conditions.
Briefly, the present invention comprises an improved blast shield protecting the passenger compartment of a wheeled military vehicle from land mine blast, the blast shield being adapted to interact with the doors to the compartment. The vehicle has a compartment for use by personnel, the compartment having a door hinged to the compartment that has a swing path that opens outward with respect to the compartment for ingress and egress. The ballistic blast shield is located on the under side of the vehicle and serves to protect the vehicle occupants in the event of a land mine detonation if the vehicle passes over a land mine. The improved blast shield of this invention has a reactive portion that responds to the force of a mine blast to move from a first ready position near the bottom edge of the door to a second blocking position. When the reactive portion is in the first ready position the door can be easily opened. When the reactive portion has moved to its second blocking position, it will prevent the door""s movement along the swing path and retain the door in a closed position as long as there is a significant blast effect acting on the shield. The blocking action will protect the occupants from being ejected from the vehicle for the duration of the blast effect and keep the door closed to prevent debris from entering the passenger compartment. Depending upon blast force, the reactive portion may return to an unblocking position. Combat vehicles are also made with a roof exit so any crew and passengers can always exit even if the doors remain blocked.